Helicobacter pylori: present status and future prospects in Japan

Abstract

The discovery of Helicobacter pylori has already changed the natural history of peptic ulcer disease, with most patients being cured at their fi rst presentation. Similarly, the incidence of gastric cancer and other diseases related to H. pylori are likely to be greatly reduced in the near future. Isolation of the spiral intragastric bacterium H. pylori totally reversed the false dogma that the stomach was sterile, and it taught us that chronic infectious disease can still exist in modern society. Helicobacter pylori's unique location, persistence, and evasion of the immune system offer important insights into the pathophysiology of the gut. Also, the fact that it was overlooked for so long encourages us to think "outside the box" when investigating other diseases with obscure etiologies. We should consider such provocative scientifi c ideas as bridges to the future disease control.

No associations of Toll-like receptor 2 (TLR2) -196 to -174del polymorphism with the risk of Helicobacter pylori seropositivity, gastric atrophy, and gastric cancer in Japanese

“…The validated criterion is PG I 70 ng/ml or less and a PG I/PG II ratio of 3.0 or less, and that for severe atrophic gastritis is PG I 30 ng/ml or less and a PG I/PG II ratio of 2.0 or less, both of which are assumed to be reliable because they are widely used in practice in Japan [31,32]. H. pylori seropositivity and PG levels were not examined in the gastric cancer cases in this study, based on the assumption that most of the gastric cancer cases would be H. pylori-positive with atrophic gastritis [33,34]. Considering that the intestinal type of gastric cancer, the predominant type of gastric cancer in Japan, arises from gastric atrophy caused by H. pylori infection, and diffuse-type gastric cancer occurs regardless of gastric atrophy [35,36], and noncardia gastric cancer is associated with H. pylori infection and gastric atrophy while cardia gastric cancer is not [37], it would be intriguing to perform subgroup analysis according to these two histological types or tumor locations.…”

Relationship between ureB Sequence Diversity, Urease Activity and Genotypic Variations of Different Helicobacter pylori Strains in Patients with Gastric Disorders

“…CagA, VacA, IceA, DupA and urease are among the most important virulence factors whose involvement in the progression of these diseases has been established (Rathbone and Rathbone, 2011 (Kusters et al, 2006;Yahav et al, 2000). Urease of H. pylori accounts for about 10% of the total cell protein that is expressed in most of the strains (Suzuki et al, 2007). This enzyme, a nickelrequiring metalloenzyme, consists of two subunits, UreA and UreB (Hu et al, 1992), which hydrolyze urea to ammonia and carbon dioxide within the gastric mucus layer to facilitate its initial interaction in this acidic environment (McGee and Mobley, 1999).…”

Molecular Epidemiology of Helicobacter pylori in Brazilian Patients with Early Gastric Cancer and a Review to Understand the Prognosis of the Disease

“…Many factors, including a high-salt diet [99], genetic abnormality [100] and autoimmune gastritis [101], among others, have been reported concerning gastric carcinogenesis; however, it is clear that H. pylori infection is the most important gastric carcinogen [60,102].…”